Draft lost when saving

Why do I lose my draft sometimes when I hit save, and the system decides out of the blue that it's time I need to re-identify myself. This is infuriating. Hard thinking lost and time wasted. It used to happen quite often and I developed a work around, but it hadn't happened for some time (maybe a year or so) but it has happened again a couple of times recently. What happens is that I start drafting, hit save, have to log in, and when I come back I've lost everything up to the previous save.

This has just happened to me as well and I am furious. A long and difficult post is now GONE. I've been working on a draft and it was saving along the way even though I was not on the internet. then all of the sudden it failed this time - the most crucial time.
FIX THIS WORDPRESS.
Is there anyway to get it back?

I was using the WordPress App for iPad 2 offline which has worked before. This time a quick message popped up the next time I went on-line, after I updated the draft an hour earlier, saying "[something]... failed". The draft reverted back to the previous draft as if I hadn't worked on it at all.

I was using the Dashboard>Posts>Add New as I don't like the New Post option. I tried to find the saved revisions underneath the newly empty except for the title post but they weren't there. I didn't know about other places to find them. I will look harder next time - I felt that as I'd done some saves, before I was thrown out to log in, that they must be there somewhere. (Infuriating though, justt the same, to be thrown out in the middle of writing a post. Why does this happen? It used to happen, then it didn't, and now it seems to be happening again.)